


De-Aged

by xMarrrvelx



Series: Stony Oneshots [Steve Rogers/Tony Stark] [2]
Category: Captain America (Movies), Iron Man (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Baby Steve, De-Aged Steve Rogers, Fluff, M/M, Natasha Romanoff speaks Russian, No Smut, Parent Tony, Superhusbands, Temporary De-Age, They're married but nothing sexual happens whilst Steve is de-aged, Tony Stark Has A Heart, Tony Stark Sings, Tony Stark speaks Italian, Tony looks after Steve, cuteness
Language: English
Status: Completed
Published: 2017-08-18
Updated: 2017-08-18
Packaged: 2018-12-17 02:31:20
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,553
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11842113
Author URL: https://archiveofourown.org/users/xMarrrvelx/pseuds/xMarrrvelx
Summary: Tony accidentally turned his husband into a toddler...so he looks after him, of course.•Just some cute Tony-being-a-parent fluff :)





	De-Aged

**Author's Note:**

> Enjoy! :)

_"Ooh! This looks interesting..."_

_"Tony, that's alien technology, don't-oof!"_

_"STEVE!"_

.

Steve was going to be fine. The effects from the magical-glowing-stick-thing were semi-permanent. All they had to do was wait.

Tony, being human and inexperienced in alien technology, didn't know whether this was actually true or not, but he kept repeating this to himself and the team anyway. They needed as much optimism as possible, because dealing with a scrawny, messy-haired, hyperactive toddler (who was also his husband, for crying out loud) was proving to be rather difficult for Earth's Mightiest Heroes. Tony would know, since he was the one who'd been juggling the child on his hip all day (the other Avengers had argued that since Steve was his husband, he should be the one to take care of him).

He and Bruce were in the lab, trying to find a solution to the issue.

"You, Steven, are quite possibly the heaviest child I've ever held," Tony said, taking his eyes away from his work for a moment to readjust the blonde in his arms. "I thought you were s'posed to be skinny?"

"He was, as a child," Bruce commented, looking over his glasses at Tony. "But the test results say differently. Look-" He grabbed the screen, and spun it around so Tony could view it. "Do you see that?"

Tony squinted, tightening his grip on Steve as he leant forward to take a closer look (Steve giggled at the sudden movement). The image clearly displayed a close-up view of a sample of blood, Steve's blood, full of red and white blood cells and numerous other normal things found in the human body. But there was something else, too. "That's..." Tony frowned. "Is that the serum?"

"Uh-huh," Bruce nodded his head. "That's usually a normal thing to see, for Steve,"

Tony nodded slowly. "Yeah, I know. But Steve's younger now, so surely the serum shouldn't still be there?"

"Exactly," Bruce replied. "But that's not the case, for some reason. I'm trying to work out why,"

"Huh," Tony bit his lip. "Yeah, that is weird,"

"I actually think it might be more to do with magic, than science. Which goes against basically everything I believe in, but, well, we know it exists, because of Strange,"

"Ugh. Magic," Tony shuddered. "Let's not repeat that dreadful word again, 'kay? And as for that Doctor-" Tony scratched his goatee. "I'm still convinced that he stole my facial hair idea,"

"You look _nothing_ alike-"

"Uh, _actually_ -"

Bruce sighed, rolling his eyes as he turned the screen around again. "Whatever. Look, I don't suppose you've found anything out about that device, have you?"

Tony shrugged. "To be honest, Bruce, I've been too busy dealing with this little one-" He gently poked Steve's nose, smiling when the young hero squealed in delight. "-to actually get any proper work done. Thor took a look at the photos and didn't think it was Asgardian, but he can't really tell, so he's gone to S.H.I.E.L.D. to get a closer look at it. That's where it-hey, what's _that_ look for?"

Bruce had been listening, but there was a small smirk on his face that told Tony there was something else on his mind. "It's nothing-"

_"Bruce-"_

"You seem to like children more then you let on, that's all,"

"I-" Tony stared at Bruce, then at Steve, who was beaming brightly at him, and then back to Bruce again. "That is completely irrelevant to what I was saying,"

"There's nothing wrong with it," Bruce said, with a smile. "It's nice, that's all,"

Tony scoffed, "Bruce, Steve's my _husband_. Of course I'm gonna be nice to him. I _love_ him,"

There was a gentle pat on his arm, and Tony looked down to see that Steve was staring at him, his bright blue eyes wide and round, an adorable smile on his face. "Wuv you too, Tony!"

Bruce stared, amazed. "He just spoke,"

"No shit, Sherlock-"

"Shut up, Watson-"

"Uh, I think you'd be Watson actually-"

"You're the one who called _me_ Sherlock in the first place!"

"It was a figure of speech!"

"Papa? Whatsa Wa'son?"

"He just spoke again!" Bruce said, ignoring Tony and grinning like a mad man. "Tony, don't you realise? That's the first time he's said a word since this whole thing happened!"

Tony's eyebrows knitted together. "Oh, yeah..." He paused, and then his face lit up. "Oh, yeah! I didn't-"

Steve was tugging at his sleeve again. "Whatsa Wa'son? Whatsa Wa'son?"

Tony grinned. "Oh my God, this is adorable,"

"I _knew_ you secretly loved this-"

"Papaaaaaaa!" Steve whined. "Whatsa Wa'son?!"

"Not a what, Steve. A _who_. Watson is a person,"

"Who's dat?" Steve questioned, his eyebrows twitching as he frowned slightly. "Papa-"

"Why does he keep doing that?" Tony looked at Bruce quizzingly.

"Doing what?"

"Papaaaaaaa-"

"That," Tony clarified. "Why is he calling me that?"

"Well," Bruce began. "I imagine it's because he's a child," He said simply. He added, "That, and the fact that you're the only one on the team who's actually spent time with him. He's naturally going to start thinking you're his parent,"

"But I'm not his dad! I'm his-"

"Papa?" Steve was wriggling in his grasp now. "Papa, I'm hungwy,"

"Oh, Lord," Tony groaned. "What do I feed him?"

"Food,"

Tony narrowed his eyes. "I hate you,"

"Well, what else am I supposed to say?" Bruce asked. "Metal?"

"Shut up,"

"Papa, dats rude,"

"I'm not your dad, kiddo," Tony muttered in reply. Steve took no notice, and continued whining, hitting the billionaire's arm lightly with his tiny fists. Tony looked at Bruce. "I'm serious. What do we have that we can give him? Can he even have solids?"

"Of course he can. He's, what, about four years old?"

"I don't know," said Tony. He gently jostled Steve in his arms, repositioning him to stop him from sliding out of his grasp. Then he looked at the blonde, and asked, "Uh...kid? How old are you, exactly?"

Steve made a small hum. "Erm..." After a moment, he grinned goofily, showing off his baby teeth. "Fwee!" He held up seven fingers. Tony laughed.

"Three years old, huh?" He said, then added, jokingly, "Not ninety?"

"Don't be silly, papa!" Steve giggled. "I'm not dat old, not wike you!"

Bruce snorted.

"Excuse me," Tony scoffed, narrowing his eyes and poking Steve in the nose again. "I'm middle aged, thank you very much!" Steve giggled.

"Keep telling yourself that, Tony," Bruce commented. He waved his hand aimlessly in the air. "Now go and get the child some food,"

"Oh, yeah, nearly forgot about that," Tony replied, using his free hand to save and close his work, an amused smile on his face. ("Tony, Tony, Ton-ee! Hehehe, dat's funny! To-nee! Tooooonnnnyyyyy..."). After about a minute of listening to Steve giggling away to himself, he said, "Right, kiddo. Let's go get you some food, yeah?"

"I'll get J.A.R.V.I.S. to let you know if I need you for anything," Bruce said.

"Okay. Thanks, Bruce,"

"No problem. Have fun,"

"Uh-huh," Tony replied, moving Steve to the other side of his body to rest his arm. "See ya,"

"Bye, Unca Bwucie!"

.

"You're incredibly cute as a baby, Steve," Tony said quietly, scooping some more yoghurt onto the spoon. "But I can't wait to get my husband back,"

Steve swallowed the yoghurt that was already in his mouth, and wrinkled his nose. "I don' wike it!"

"Oh, really?" Tony shook his head. "Sorry, but you've got to eat this stuff, kid,"

"Don't wanna!"

"C'mon, now," Tony grabbed the spoon, and began making childish noises. "Here comes the, uh-" _Lord_. "-the Yoghurt Train! Choo choo!"

Steve shook his head, stubbornly pressing his lips together. As Tony brought the spoon closer, Steve unexpectedly began kicking his legs, which shook the high chair slightly (yes, they had a high chair. Tony didn't know why, or how, but used it anyway. After all, what else was he supposed to do with it?). And then, just as the spoon neared his lips, he started to yell.

"Stop it!!"

Tony widened his eyes. "Steve, c'mon, it's just yoghurt. Be a good boy? Choo ch-"

"No!" Steve was literally screaming now. "No trains! I don't wike trains!!"

Oh, God, Tony had not signed up for this. Quickly, he shoved the spoon back into the yoghurt pot, raising his empty hands in the air. "Woah...Jesus, Steve, look, there's no trains, see?"

Steve had his tiny hands placed over his eyes, so, no, he couldn't see. Tony sighed, standing up. He took hold of the toddler's wrists, and gently pried them away from his face, but Steve kept his eyes clenched shut, so Tony opted for lifting Steve out of the high chair instead. Holding the squirming child to his chest, he ran his fingers through the child's hair, something that Steve (though he would never admit it) usually loved.

"It's okay, Steve, there's no trains. Just you and me,"

Steve had stopped struggling, but his eyes were still tightly closed, and he was still clearly upset over...a fake train that didn't even resemble a train? Tony frowned, wondering what on earth could've caused such a reaction.

"Steve?"

"Papa... " Christ, his voice sounded so...small. "Papa, don't weave me,"

 _What the hell?_ "Steve, sweetheart, I'm not going to leave you," _I was just feeding you some yoghurt-_

"B-Bucky weft me," Steve whispered. Tony raised his eyebrows. "Don't...don' be like Bucky..."

Oh.

"I-" Tony wasn't sure what to say. "You-you remember Bucky?"

Steve nodded his little head. "Bucky was on a train," He pouted slightly. "And then...he weft, papa, but I-I can't 'member-"

"That's...odd," He knew exactly what Steve was talking about, because the blonde had told him this story numerous times before. But to hear it coming out of six-year-old-Steve's mouth confused him, because that particular event occurred way after Steve's current age, which...didn't make a lot of sense, really. _Magic_. Tony thought. _Ugh_.

"I'm sowwy,"

"What?" Steve had finally opened his eyes, and he was gazing up at Tony with them, full of unspilt tears. "No, Steve, I wasn't-I didn't mean you were odd, I just-"

Steve ducked his head. "Papa?" He mumbled into Tony's chest.

"Yeah, Steve?"

Steve placed his small right hand against Tony's Arc Reactor, then shifted slightly in Tony's arms, and pressed his ear against the cool metal, listening to it's steady hum. Tony smiled, his heart warming at the touch, because Steve looked so cute, and so peaceful. Ever so softly, Steve murmured, "Pwomise dat you won' leave me?"

"Oh, Steve," Tony held him closer, and pressed a kiss into the child's hair (it smelt rather strongly of apple, which was odd, but Tony didn't comment on it). "Of course I'm not going to leave you. I'll always be here when you need me,"

"Always?"

"Yeah, Steve. Always,"

Steve gave a happy, content sigh, and nestled further into Tony, closing his eyes.

"Aww, that was nice. I didn't realise you were so fond of kids,"

Tony rolled his eyes, turning around. Stood in the doorway of the communal kitchen was Clint and Natasha. The latter simply smiled, but the former was full on smirking. Tony narrowed his eyes, but didn't say a word, and pointed his index finger at Steve, who, he was almost one-hundred percent certain, was now fast asleep. Both assassins nodded their heads, though Clint still had that look on his face. Tony gave him a look too.

Natasha pointed at him, then waved her hand. _Follow me._ Then she disappeared behind the doorway.

Frowning, Tony looked over at Clint, who just nodded his head in the direction that Natasha had walked off in. He too then headed that way. Tony looked down at Steve, who was still sleeping soundly, and then decided to follow the pair. They were only a few steps in front of him, but Tony stayed where he was, avoiding rushing ahead to join them so as not to wake up the blonde in his arms.

After a short elevator ride, the four of them ended up outside one of the guest bedrooms. Tony eyebrows twitched into a confused frown, but Natasha said nothing. Wordlessly, she opened the door, and-

Wow, they'd been busy.

The once boring, plain guest room had been turned into a child's paradise, full of toys and books, and all sorts of wondrous things, each a shade of red, white, or blue. The walls were covered in posters and canvases that all displayed things to do with superheroes, and the large double bed had been transformed, and now, instead of it's usual white sheets, was entirely Captain America themed. Tony couldn't help but smile when he noticed the two plush toys that were centred on the pillows: Captain America and Iron Man.

He raised his eyebrows, impressed. "You guys know that this whole 'Steve-is-a-child' thing isn't permanent, right?" He whispered.

"Shh," Natasha replied. "Put the _malen'kiy_ to bed first, then we can talk," 

Tony nodded. Using his back to push open the door, he stepped into the room. He took a few seconds to marvel at all of the decorations, and then slowly lowered Steve onto the bed. The blonde stirred slightly, his eyelids half open.

"Pa...?"

"Shh," Tony whispered, grabbing a nearby blanket and wrapping it around Steve. "It's okay. Go to sleep, _tesoro_ ," [sweetheart] He brushed a few hairs that had fallen away from Steve's forehead, and pressed a light kiss there. _"Vai a dormire adesso,"_ [go to sleep now]

"G'Night, papa..."

"Goodnight, Steve,"

Tony rose from the bed, smiling.

"That was the cutest thing I've ever seen," Clint said, as soon as Tony had closed the door. "Or heard, for that matter. Tesoro? Vai a dormire adesso? That's what you said, right? I didn't know you could speak Italian,"

"There's a lot you don't know about me, Hawkass," Tony said. He shrugged. "I learnt most of it from my mother,"

"Oh?" Natasha tilted her head. "You've never mentioned it before,"

"It never came up," Tony waved his hand, dismissing the subject. He wasn't really fond of speaking about his parents. "But, anyway...since when were you two experts in interior design? And where did you even get the money for all of this?"

"You're a billionaire," Clint deadpanned, as though that explained everything.

"Right," Tony said. "Okay. Well, I'm sure Steve appreciates it and everything, but you really didn't have to go to all of that trouble. It's not like Steve's going to stay this way forever,"

"Well," Clint said, quietly. "You don't know for sure-ow!" Natasha sleeve-slapped him on the back of the head.

"Idiot," She hissed, narrowing her eyes. "Don't say such things,"

Tony pretended not to notice, but the words stayed in his mind nonetheless. You don't know for sure. It was true, though, wasn't it? Tony had no idea about how magic worked, or even if it was magic that had made Steve this way, and he definitely had no clue as to how to fix it. Steve was adorable like this, but what if he stayed a three-year-old forever? What if Tony never saw his husband properly again?

"Tony," Natasha said, softly. "I can practically hear your worried thoughts right now. Stop it. Steve's going to be fine,"

"Yeah, but," Tony twirled the wedding band on his finger. "What if-"

"Steve is going to be fine," Natasha said, more sternly this time. "Okay? Bruce is going to fix this,"

"That reminds me, actually," Tony said, changing the subject and trying to hide the worry in his voice. "I need to see Bruce later," He was talking to himself, really (he wasn't crazy, he just did that sometimes, okay?) but Clint replied anyway.

"Oh, yeah?" He asked. "What about?"

"Uh, nothing really," Tony shrugged. "Just something that happened with Steve earlier-"

"What? Is he okay?"

"Huh? Oh! Yeah, yeah, I think so, anyway. It's just that, well, I think his memories are a bit mixed up. One minute, he's acting the way a usual toddler would. The next minute, well..." Tony paused. "It was weird, but, he started talking about Bucky?"

Natasha frowned. "Yeah, that is kinda strange," She said. "Maybe it's a good thing, though. Maybe he's getting his old memories back. Maybe he's going to turn back to normal soon,"

"I sure as hell hope so," Tony muttered. "But, uh, yeah. I should probably go find Bruce before it gets too late. Can you, er...would you mind watching Steve? Just...make sure he's alright, yeah?"

"'Course," Natasha promised.

"Yeah," Clint agreed. "We'll let you know if you're needed,"

"Thanks, guys," Tony smiled, then said his goodbyes and headed towards Bruce's lab.

.

Tony wasn't sure what time it was, exactly, but he was listening to Bruce go on about some new test results, when the scientist's words trailed off into nothing. He was staring at something behind Tony, over his shoulder, and then he raised his eyebrows and nodded in that direction.

"Uh, Tony?" He said, slowly. "I think you're needed somewhere else..."

"Wha-" Tony's eyebrows knitted together, and he spun around to see where Bruce was looking. "Oh,"

Steve, the poor little thing, was stood in the doorway, crying his eyes out. He held tightly onto a blanket in one hand that mimicked his shield _(I bet Clint bought you that, huh?)_ and in his other he clutched the Iron Man plushie.

"P-Papa..."

"I see that Nat and Clint took good care of you, then," Tony said, sarcastically, as he rushed over to the child. He slowly crouched down, so that he was at the same level as him. "What's wrong? Did you have a nightmare? Hmm?"

Steve nodded his head, squeezing his eyes shut. "M'cold," He was shivering, too.

"C'mere," Tony said, softly, enveloping Steve in a hug. Had he dreamt about the ice? "It's okay, see? No one's going to hurt you. You're safe now," Tony carefully scooped Steve up in his arms, making sure that he didn't leave the blanket and toy behind. He made eye contact with Bruce.

"I'm gonna go put him to bed," Tony told Bruce. "If you see The Terrible Twosome, let them know that they're idiots for allowing a small child to toddle around near a laboratory unprotected,"

"Will do," Bruce complied. "Though I'm sure it wasn't intentional,"

"Yeah, well, I'm still annoyed," Tony huffed. He kissed Steve's head. "C'mon, squirt, let's get you back in bed, yeah?"

Steve nodded against Tony's chest, drawing a fist up to his face to dry his eyes.

Tony wasted no time in getting back to Steve's new room. The door had been left ajar, and Tony nudged it further open with his foot, stepping into the well-decorated room. Like before, he set Steve down on the bed, tucked him in, gave him the two teddies, and kissed his forehead. Only this time, as Tony turned to leave, Steve's small fingers managed to grasp onto his t-shirt, and he tugged lightly on the material.

"Pwease stay," Steve whispered, somehow managing to do puppy eyes (AKA Tony's weakness) despite being so young.

Tony just couldn't say no to that face.

"Alright, then," He replied quietly, a small smile on his face. He drew back the covers, and climbed in next to the small child, despite the fact that he was still dressed in his regular Black Sabbath t-shirt and jeans. Whatever. Steve hummed happily, and automatically pressed himself against Tony, a tiny smile on his face that was illuminated by the soft blue glow of the Arc Reactor. The genius wrapped a protective arm around him, pulling him closer. "Go to sleep, now, tesoro," [sweetheart] Steve probably had no idea what that meant, but his smile widened nonetheless.

He seemed to take a lot longer to drift off than before, though.

Tony frowned slightly. He was tired, but he kept refusing to go to sleep until Steve did, which seemed to be taking a while. And so he did the one thing that he hadn't done for years.

He sang.

His singing voice was slightly rough, unused after all those years, but he still sang in tune. _"Fa la ninna, fa la nanna, nella braccia della papá,"_ It was an old Italian lullaby, sung to him as a child, and it seemed to be doing the trick. " _Fa la ninna bel bambin, fa la nanna bambin bel,"_

[Go to sleep, go to sleepy,  
In the arms of your father,  
Go to sleep, lovely child,  
Go to sleepy, child so lovely]

Steve gave a small, barely audible sigh, and though he had no idea what the words meant, he was smiling as his eyelids fluttered closed. "Wuv you, papa..."

Tony smiled fondly, and kissed Steve on the forehead again. "I love you too, Steve. _Fa la ninna, fa la nanna nella braccia della papá..."_

[Go to sleep, go to sleepy,  
In the arms of your father]

After a while, Tony's eyes closed too.

.

  
When Tony awoke the next morning and saw that Steve had changed back to his regular self, he yelped in surprise-

"Steve!"

-and fell off the bed.

"Tony? What in God's name are we doing in _here?"_ A pause. "And why are you on the _floor_?"

 

fin.


End file.
